diff --git a/control/context.c b/control/context.c
index d57b0f1e697f6c423b7146929f01092d32bf0599..4e0a6672bb20ddb3658c7e50ee4bcf58a323b1db 100644
--- a/control/context.c
+++ b/control/context.c
@@ -59,8 +59,8 @@ CHAM_context_t *chameleon_context_create()
 
     /* These initializations are just in case the user
        disables autotuning and does not set nb and ib */
-    chamctxt->nb                 = 128;
-    chamctxt->ib                 = 32;
+    chamctxt->nb                 = 320;
+    chamctxt->ib                 = 48;
     chamctxt->rhblock            = 4;
     chamctxt->lookahead          = 3;
 
@@ -69,7 +69,7 @@ CHAM_context_t *chameleon_context_create()
     chamctxt->nthreads_per_worker= 1;
 
     chamctxt->warnings_enabled   = CHAMELEON_TRUE;
-    chamctxt->autotuning_enabled = CHAMELEON_TRUE;
+    chamctxt->autotuning_enabled = CHAMELEON_FALSE;
     chamctxt->parallel_enabled   = CHAMELEON_FALSE;
     chamctxt->profiling_enabled  = CHAMELEON_FALSE;
     chamctxt->progress_enabled   = CHAMELEON_FALSE;
diff --git a/runtime/starpu/control/runtime_descriptor.c b/runtime/starpu/control/runtime_descriptor.c
index 9c837e5b4c335f6acb49ab59387425f8bb69f971..24ae67e66aed8aeb96a8de68771f551ac1595ffb 100644
--- a/runtime/starpu/control/runtime_descriptor.c
+++ b/runtime/starpu/control/runtime_descriptor.c
@@ -30,8 +30,8 @@
 /* Take 24 bits for the tile id, and 7 bits for descriptor id.
  These values can be changed through the call CHAMELEON_user_tag_size(int tag_width, int tag_sep) */
 #define TAG_WIDTH_MIN 20
-static int tag_width = 31;
-static int tag_sep   = 20;
+static int tag_width = 64;
+static int tag_sep   = 50;
 static int _tag_mpi_initialized_ = 0;
 
 static inline int